Failure of athymic-nude mice sensitized with Bacillus Calmette-Guérin to produce interferon in response to purified protein derivative.

Unlike their +/+ and nu/+ littermates, homozygous athymic-nude (nu/nu) mice that had been sensitized with Bacillus Calmette-Guérin (BCG) failed to produce interferon (IFN) in response to purified protein derivative (PPD). Likewise, spleen cells derived from BCG-sensitized nu/nu mice failed to produce IFN when exposed to PPD in vitro. These findings suggest that the T-cell subset that responds to specific antigens (i.e., PPD) is absent in athymic-nude mice.